1. Field of the Invention
This invention relates generally to speakers and, more particularly, to a woofer that is capable of producing a dynamic flashing light show depending upon the volume and frequency of the sound to be emitted thereby.
2. Background Art
A woofer is a well known type of speaker that reproduces audio sounds that are usually first amplified by an audio amplifier. However, the ornamental appearance of conventional woofers is independent of the sounds that are emitted therefrom. That is to say, the appearance of the woofer does not change regardless of the frequency and volume of the sounds that are heard by a listener. Therefore, the conventional woofer is, in and of itself, completely passive and has no effect on the emotions or feelings of the listener.
In certain cases, it has been known to associate an ornamental light emitting diode (LED) display with a speaker. Such speakers typically have control circuitry located on an exterior surface thereof. Since the LEDs are usually located far from the control circuitry, such LEDs require complicated circuitry having many connections which has heretofor resulted in malfunctions. In some cases, signal delays are introduced which cause the flashing light effect produced by the LEDs to be out of sync with the sound (e.g. music). In cases where the LEDs are placed around the outside of the speaker, the appearance of the speaker is often negatively effected. What is more, installation of these speakers is complicated in areas where little space is available, such as in a motor vehicle. Consequently, the conventional speakers having a flashing light capability are characterized by a large size, an undesirable crowded appearance and a flashing light display which does not always track the volume and/or frequency of the emitted sounds.
One example of a woofer which has a flashing light capability is available by referring to U.S. Pat. No. Des 442,945 issued May 29, 2001.
A woofer is disclosed having either one or two LEDs and a control circuit that are conveniently mounted on a printed circuit board at the center of the woofer at an inconspicuous location under a transparent dust cover so as to achieve a compact configuration without effecting the aesthetic appearance of the woofer. The woofer receives an AC input from the output of an audio amplifier. A diode rectifier transforms the AC input into a DC voltage for driving the LEDs. Accordingly, the LEDs are capable of generating a flashing light show depending upon the output of the audio amplifier and the volume and frequency of the sounds that are reproduced by the woofer.
The woofer includes a hollow shell that surrounds the printed circuit board on which the LEDs and control circuitry are mounted. The hollow shell has an inside cone and an outside frame that are joined together at a resilient (e.g. rubber) lip that extends around the outermost edge of the shell. The inner cone of the shell is attached (e.g. glued) to a voice coil housing that lies below the dust cover so as to enclose the LED printed circuit board. A single voice coil or dual voice coils are wound around the voice coil housing. The woofer has a magnetic structure including a T-yoke to carry a plurality of permanent magnets and an inner core around which the voice coil housing is slidably received. The voice coil, which is connected to AC input terminals of the woofer, receives an alternating current, such that when the polarity of the voice coil and the permanent magnets are identical, the voice coil will be attracted towards the permanent magnets. In this case, the voice coil housing around which the voice coil is wound will slide downwardly over the inner core of the magnetic structure so as to pull the resilient lip around the woofer shell radially inward. When the plurality of permanent magnets and the voice coil are at opposite polarities, the voice coil will be repelled by the magnets. In this case, the voice coil housing will slide upwardly over the inner core to push the resilient lip of the woofer shell radially outward. Accordingly, a dynamic push-pull magnetic effect is created that causes the woofer shell to be compressed and expanded in a manner that tracks the sounds being emitted by the woofer.